// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
#define UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
#include "ui/gfx/geometry/safe_integer_conversions.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/gfx_export.h"
#include <iosfwd>
#include <string>
namespace gfx {
class GFX_EXPORT ScrollOffset {
public:
    ScrollOffset()
        : x_(0)
        , y_(0)
    {
    }
    ScrollOffset(double x, double y)
        : x_(x)
        , y_(y)
    {
    }
    explicit ScrollOffset(const Vector2dF& v)
        : x_(v.x())
        , y_(v.y())
    {
    }
    explicit ScrollOffset(const Vector2d& v)
        : x_(v.x())
        , y_(v.y())
    {
    }
    double x() const { return x_; }
    void set_x(double x) { x_ = x; }
    double y() const { return y_; }
    void set_y(double y) { y_ = y; }
    // True if both components are 0.
    bool IsZero() const
    {
        return x_ == 0 && y_ == 0;
    }
    // Add the components of the |other| ScrollOffset to the current ScrollOffset.
    void Add(const ScrollOffset& other)
    {
        x_ += other.x_;
        y_ += other.y_;
    }
    // Subtract the components of the |other| ScrollOffset from the current
    // ScrollOffset.
    void Subtract(const ScrollOffset& other)
    {
        x_ -= other.x_;
        y_ -= other.y_;
    }
    Vector2dF DeltaFrom(const ScrollOffset& v) const
    {
        return Vector2dF(x_ - v.x(), y_ - v.y());
    }
    void operator+=(const ScrollOffset& other) { Add(other); }
    void operator-=(const ScrollOffset& other) { Subtract(other); }
    void SetToMin(const ScrollOffset& other)
    {
        x_ = x_ <= other.x_ ? x_ : other.x_;
        y_ = y_ <= other.y_ ? y_ : other.y_;
    }
    void SetToMax(const ScrollOffset& other)
    {
        x_ = x_ >= other.x_ ? x_ : other.x_;
        y_ = y_ >= other.y_ ? y_ : other.y_;
    }
    void Scale(double scale) { Scale(scale, scale); }
    void Scale(double x_scale, double y_scale)
    {
        x_ *= x_scale;
        y_ *= y_scale;
    }
    std::string ToString() const;

private:
    double x_;
    double y_;
};
inline bool operator==(const ScrollOffset& lhs, const ScrollOffset& rhs)
{
    return lhs.x() == rhs.x() && lhs.y() == rhs.y();
}
inline bool operator!=(const ScrollOffset& lhs, const ScrollOffset& rhs)
{
    return lhs.x() != rhs.x() || lhs.y() != rhs.y();
}
inline ScrollOffset operator-(const ScrollOffset& v)
{
    return ScrollOffset(-v.x(), -v.y());
}
inline ScrollOffset operator+(const ScrollOffset& lhs,
    const ScrollOffset& rhs)
{
    ScrollOffset result = lhs;
    result.Add(rhs);
    return result;
}
inline ScrollOffset operator-(const ScrollOffset& lhs,
    const ScrollOffset& rhs)
{
    ScrollOffset result = lhs;
    result.Add(-rhs);
    return result;
}
inline Vector2d ScrollOffsetToFlooredVector2d(const ScrollOffset& v)
{
    return Vector2d(ToFlooredInt(v.x()), ToFlooredInt(v.y()));
}
inline Vector2dF ScrollOffsetToVector2dF(const ScrollOffset& v)
{
    return Vector2dF(v.x(), v.y());
}
inline ScrollOffset ScrollOffsetWithDelta(const ScrollOffset& offset,
    const Vector2dF& delta)
{
    return ScrollOffset(offset.x() + delta.x(),
        offset.y() + delta.y());
}
// This is declared here for use in gtest-based unit tests but is defined in
// the gfx_test_support target. Depend on that to use this in your unit test.
// This should not be used in production code - call ToString() instead.
void PrintTo(const ScrollOffset& scroll_offset, ::std::ostream* os);
} // namespace gfx
#endif // UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
